Technical Field
The present disclosure relates to a surgical stapling device and more particularly to a surgical stapling device having pusher-engaging cam members that are slidable on offset planes.
Background of the Related Art
There are several known types of surgical stapling instruments specifically adapted for use in various procedures. In many such surgical devices, tissue is first grasped or clamped between opposing jaw structures and then joined by surgical fasteners. The fasteners are typically in the form of surgical staples. These staples generally include a pair of legs adapted to penetrate tissue and connected by a backspan from which they extend. In use, the staples are formed to a “B” configuration. Two-part fasteners are also known and include legs that are barbed and connected by a backspan which are engaged and locked into a separate retainer piece that is usually located in the anvil. In some devices, a knife is provided to cut the tissue which has been joined by the fasteners.
In these devices, one of the jaw structures carries a staple cartridge having one or more laterally spaced rows of staples, which are aligned with corresponding rows of anvil depressions on an opposing jaw structure. The tissue is initially gripped or clamped such that individual fasteners can be ejected from the cartridge, through the slots, and forced through the clamped tissue. The staples are ejected by longitudinal movement of a driver and forced through the clamped tissue, forming against the staple forming depressions of the anvil. The staples can be arranged in a linear or non-linear row.
A common issue in transecting tissue and/or in anastomosis procedures employing the surgical stapling instruments is the balance between anastomotic strength and the degree of hemostasis achievable. It is known to include different size staples in a surgical stapling instrument having a constant gap (uniform distance) between an anvil and a staple cartridge.
A common concern in these surgical procedures is hemostasis, or the rate at which bleeding of the target tissue is stopped. It is commonly known that by increasing the amount of pressure applied to a wound, the flow of blood can be limited, thereby decreasing the time necessary to achieve hemostasis. To this end, conventional surgical fastening apparatus generally apply two or more rows of fasteners about the cut-line to compress the surrounding tissue in an effort to stop any bleeding and to join the cut tissue together. Each of the fasteners will generally apply a compressive force to the tissue sufficient to effectuate hemostasis, however, if too much pressure is applied, this can result in a needless reduction in blood flow to the tissue surrounding the cut-line. Accordingly, the joining of tissue together in this manner may result in an elevated level of necrosis, a slower rate of healing, and/or a greater convalescence. On the other hand, if not enough pressure is applied, proper hemostasis may not be achieved.
Consequently, it would be advantageous to provide a surgical fastening apparatus capable of limiting the flow of blood in the tissue immediately adjacent the cut tissue to effectuate hemostasis and wound closure, while maximizing blood flow in the surrounding tissue to facilitate healing.